Combination radiant and convection heating system



Aug. 28, 1956 w. w. PARKS ETAL 2,760,726

COMBINATION RADIANT AND CONVECTION HEATING SYSTEM Filed Oct. 6, 1954 3Sheets-Sheet 1 BLOWER {1 FAN Q ClECULAT/NG PUMP az s 6 5:17:51 SW. 78 5;

igfi 7% T 7. INVENTORS 1 M. WILLIAM W. PARKS l WILLIAM l2. PETERSON I7/MWW Aug. 28, 1956 w. w. PARKS ET AL 7 2,760,726

COMBINATION RADIANT AND CONVECTION HEATING SYSTEM Filed Oct. 6, 1954 aSheds-Sheet 2 INVENTORS WlLLrAM W. PARKS WILLIAM l2. PETERSON 6 y/flwmW4. W

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Aug. 28, 1956 w. w. PARKS ET AL COMBINATION RADIANT AND CONVECTIONHEATING SYSTEM Filed Oct. 6, 1954 3 Sheets-Sheet 5 3 6 3 3| A?! 7 5 A Mp /HW 1 1 I 3 9 a i 3 5 a a z a A 1 A i 7 Ill/ M w s M Tm. in W wwn M M7- M M W J fifl WW7 B n00, ran/"1111111111111 COWINATION RADIANT ANDCONVECTION HEATING SYSTEM William W. Parks, Oak Park, and William R.Peterson, Skokie, Ill, assignors to Vapor Heating Corporation, Chicago,11L, a corporation of Delaware Application October 6, 1954, Serial No.460,632

11 Claims. (Cl. 23743) The present invention relates to a combinationradiant and convection heating system. It has been designed for useprimarily in connection with the heating of buses, house trailers orother road vehicles. The system is, however, by suitable modification,capable of other uses; for example, the heating of railway passengercars and other similar vehicles.

Specifically, the invention relates to an improved heating system forroad or railway vehicles wherein the heat ing effect obtained within theenclosure to be heated is partly the result of heat radiation from themain floor of the vehicle and partly the result of heat convection byvirtue of the forced passage of air into contact with the heated floorsurfaces and the direction of the thus heated air into the enclosure atsuitable locations through passages provided for this purpose.

Briefly, the invention contemplates the provision of an interlockingsectional floor structure proper which, when placed in position on thesub-floor, provides a comparuncnted space therebeneath. The variousfloor sections are made of high heat conductive metal and each sectionis formed with an open trough portion that extends transversely of thevehicle. The trough portions extend in spaced parallelism in such amanner that, after the floor has been installed on the sub-floorsupporting surface, a continuous heating coil may be placed inserpentine fashion within the troughs and connected to a source ofheating media; for example, heated liquid or steam. The open troughswith the heating coil disposed therein are closed by cover plates which,together with the floor sections, form a continuous upper plane floorsurface. The underneath convex surface of the trough portion of eachmetal floor section extends from wall to wall through its respectivecompartment and presents a relatively larg surface area so that airissuing from a central longitudinal manifold conduit, common to and incommunication with the various compartments, may pass beneath this heatradiating surface and absorb heat therefrom. The thus heated air dividesand passes laterally in opposite directions into the hollow wallstructures of the vehicle from whence it issues through suitable grillesinto the interior passenger compartment. The heating system furtherincludes a heater and a circulating pump for the heated liquid and ablower for forcing air through the passages provided for it, togetherwith suitable thermostatically controlled means whereby uniformtemperature conditions may be maintained throughout the enclosure formaximum occupant comfort.

A trailer coach or other small vehicle is difficult to heatsatisfactorily by radiant means :alone because of the disproportionatearea of the floor and side walls relative to the size of the enclosure.In such case there is a pronounced tendency to overheat localized areasof the heat radiant surfaces and thereby provide hot spots at localizedareas. it is, therefore, a principal object of the present invention toprevent the overheating of localized areas of the heat radiatingsurfaces by circulating air in contact 'nited States Patent with saidsurfaces so as to absorb heat therefrom, the heated air being deliveredinto the enclosure.

The above described construction makes possible the attainment ofnumerous objects, principal among which is the ease of assembly of thefloor structure and the placement of the heating equipment therein, thelatter being capable of installation after the floor proper has beenlaid.

Another object of the invention is the provision of a sectional floorstructure which presents a continuous smooth unbroken floor surfacebeneath which the continuous heating tube or conduit is Widelydistributed and effectively embedded, yet in which all portions of thetube are readily accessible for purposes of inspection, replacement orrepair without disturbing the individual sections of the flooring.

The invention is illustrated in certain preferred embodiments in theaccompanying drawings, wherein:

Fig. 1 is a perspective view, somewhat schematic in its representation,of an enclosed vehicle, for example, a house trailer to which theheating system of the present invention has been applied;

Fig. 2 is an enlarged horizontal sectional view taken through the rearportion of the vehicle immediately above the floor level thereof;

Fig. 3 is a sectional View taken substantially along the line 3-3 ofFig. 2;

Fig. 4 is a fragmentary sectional view taken substantially along theline 44 of Fig. 2;

Fig. 5 is a sectional view similar to Fig. 4 showing one .of the coverplates employed in connection with the invention partially removed;

,Fig. '6 is a fragmentary sectional view similar to Fig. 3 showing amodified form of heated floor structure;

Fig. 7 is a sectional view taken substantially "along the .line 77 ofFig. 6; and

Fig. 8 is a circuit diagram of the heating system.

Referring now to the drawings in detail and particularly to Fig. 1, theheating system of the present invention has been shown as being appliedto a house trailer coach it) but it will be understood that theillustration is purely exemplary and the system may, with or withoutmodification, be used for the heating of buses or other road vehi- :clesor rolling stock such as railway passenger cars.

The coach 10, with certain exceptions that will appear presently, is ofconventional design and includes a composite floor 11, composite sidewalls 12 and 13 (Figs. 2 land 3) and front and rear Walls 14 and 15. Thecoach further includes a top wall or roof 16 which is preferably of aninsulated type and which bears no specific relation to the presentheating system other than to complete the trailer enclosure 17undergoing heating.

As shown in Figs. 2 to 5 inclusive, the composite floor 11 comprises asub-floor 20 supported from a pair of inturned. flanges 21 provided on:a pair of metal side sills or beams 22 which extend longitudinally ofthe coach. The sub-floor is preferably composed of suitable insulatingmaterial.

The sub-floor 20 is provided with a central longitudinally extendingtrough 23 therein which is preferably rectangular in cross section and atubular metal conduit 24 fills the trough coextensively and has itsupper surface flush with the upper surface of the sub-floor. The conduit24 provides an air conduit for distribution of air in a manner that willbe made clear presently.

Supported on the sub-floor 2G and terminating short of the two sideWalls 12 and 13 are a plurality of transversely extending interlockingmain floor members or channels 25 (Figs. 2, 4, and 5) having dependingside flanges 26 and 27, the inturned ends 28 of which rest upon thesub-floor. The side flanges 26 and 27 are connected across their tops bysurface panels 29 having medial longitudinally extending heat radiatingribs 30 formed thereon and which also function as strengthening members.The side flanges 26 are formed with protuberances 31 which fit intorecesses 32 provided in the side flanges 27 immediately below thesurface panel 29. Each channel 25 forms, in combination with thesub-floor 20, an inner air space or duct 33. The channels 25 arepreferably formed of aluminum on account of the lightness and excellentheat-conducting qualities of the same.

Each of the channel members 25 has formed in its upper surface panel 29a longitudinally extending trough portion including a trough proper 34and horizontal ledge portions 35 and 36 which are offset from the planeof the surface panel 29. The portion 35 merges with an undercut recess37 adapted to mate with the bevelled edge 38 of an elongated cover plate39 having a curved underneath surface 40. The cover plate 39 is adaptedto have its edgeregions supported upon the upper surface of the ledgeportions 35 and 36 and a series of clamping screws 41 serve to anchorthe cover plate 39 in position so as to close the upper side of thetrough portion 34.

As shown in Figs. 1 to 3 inclusive, coils of a continuous tubing 42 arearranged within the trough portions 34 of the various channel members 25in serpentine fashion so that the coil bends 43 project over the ends ofthe channels as shown in Figs. 1 and 2. The tubing 42 is formed of metaland the walls thereof are relatively thin so that high and rapid heatconductivity through the walls will be attained and also so that slightdeformation of the cross sectional shape of the tubing may take placewhen the cover plates 39 are secured in position over the troughs 34 toforce the metal of the tubing into intimate heat-transfer contact withthe surrounding metal of the floor assembly.

The side Walls 12 and 13 are of similar construction and each wallincludes an outer panel 44 and an inner panel 4-5 spaced therefrom so asto provide an air space 46 therebetween. The space 46 communicates withthe enclosure 17 through suitable grilles 47 preferably situatedimmediately beneath the sills of the various coach windows 43 (Fig. 1).An elongated blocking strip or seal 50 extends horizontally between eachpair of walls 44, 45 and seals off the upper portion of the space 46 andserves to direct air inwardly to the compartment 17 through the variousgrilles 47.

As shown in Figs. 2 and 3, the tubular metal conduit 24 is provided witha plurality of openings 51 in the top wall thereof which establishescommunication between the interior of the conduit and each of the airspaces or ducts 33. The rear end of the conduit 24 is operativelyconnected to a conventional air blower or fan 52 (see also Figs. 1 and8) driven by a motor M1. Air issuing from the fan 52 and entering theconduit 24 is forced under pressure into the various ducts 33 and equaldistribution of the volume of air delivered to the ducts may be attainedby graduating the size of the ports 51 along the conduit.

The continuous serpentine tubing 42 is connected in and forms anintegral part of a closed fluid heating circuit utilizing hot Water oran anti-freeze solution such as ethylene glycol as the heating medium,although other heating media such as steam is contemplated. The heatingcircuit extends from a suitable heating coil 60 (Fig. 1) through a pipesection 61 leading to a pump 62 driven by a motor M2 and from thence toa T-fitting 63 where the circuit branches into two loops 64 and 65having return lines 66 and 67 respectively leading back to the heatingcoil 60 through a conduit 68.

A heater 70 is positioned beneath the heating coil 60 and may besupplied with propane, kerosene or other suitable fuel contained withina fuel tank 71. Obviously, any form of heating means may be substitutedfor that shown, whether electrical or of the fuel burning type.

In the operation of the system, the control mechanism shown in Fig. 8serves to maintain uniform temperature conditions throughout theenclosure 17 undergoing heating. A thermostat T is positioned within theenclosure at a suitable location and an aquastat A is interposed withinthe heating fluid line. The thermostat T is provided with a mercurycolumn 72 adapted to bridge a pair of contacts 73 and 74 when apredetermined maximum temperature is attained within the enclosure. Thecontacts 73 and 74 are disposed in an electrical circuit leading fromthe negative side of a source of current such as an automobile battery,through a current limiting resistor 75, the contacts 73, 74, the winding76 of a normally closed solenoid actuated switch Sw to the positive sideof the line. The switch Sw is disposed in a circuit extending from thenegative side of the line through a safety switch 77 adapted to becomeopen when excessive heat is generated at the burner, the switch Sw, afuel shut-off solenoid 78 positioned in the fuel line, and the aquastatA to the positive side of the line. The motors M1 and M2 for the pump 62and fan 52 are disposed in respective circuits which become energizedupon closure of a master switch Sm.

To operate the system, the burner 70 is ignited and the master switch Smis closed and circuits are immediately established through the motors M1and M2 to operate the pump 62 and fan 52 respectively. A circuit alsowill exist through the safety switch, fuel solenoid and aquastat aspreviously described thus maintaining the flame at the burner and a freeflow of the heating fluid through the system, while at the same time airis forced into the conduit 24 from the blower fan 52. This air which isforced into the conduit 24 under pressure escapes through the slot 51and is distributed to the various air ducts 33 near the center thereoffrom whence it divides and passes laterally in opposite directions alongeach duct. During such passage of the air along the ducts 33, heat isassimilated by virtue of the intimate contact of the air with the convexsurface of the trough portion of the channel member 25. This air mayalso absorb some heat from the radiating fins 30 which become heated bydirect heat conduction from the wall of the tubing 42 through the metalof the channel member 25. Heated air issuing from the ends of thechannel members 25 enters the space existing within the side walls 12and 13 from whence it issues from the various grilles 47 and enters thepassenger compartment 17 where it serves principally to heat the upperregions of the compartment.

Heated air within the ducts 33 applies heat to the portions of the mainfloor which are too remote from the trough 34 to receive an appreciableamount of heat by direct conduction and the heated surface panels 29radiates heat into the enclosure where it serves principally to heat thelower regions of the compartment.

When the temperature within the compartment 17 attains a, predeterminedmaximum, for example 70 F., the contacts 73 and 74 are bridged by themercury column 72 of the thermostat T and the coil 76 of the switch Swbecomes energized, thus opening the switch and interrupting the circuitthrough the fuel solenoid so that the burner becomes shut down. Thissame circuit is capable of being opened under the control of theaquastat A when the temperature of the heating fluid attains apredetermined maximum. The circuit also will become open when the safetyswitch opens due to an undue rise of heat at the burner, occasioned, forexample, by insufficient fluid in the system. Obviously when thetemperature within the enclosure drops below the predetermined maximum,the circuit through switch coil 76 will be broken, thus allowing theswitch Sw to close and restore normal operation of the burner.

In Figs. 6 and 7 a slightly modified form of the structural arrangementof the coach floor has been shown although the principles of operationof the heating system remain the same as described in connection withthe other form of floor. Here the composite coach side walls consist ofan inner wall panel 101, an intermediate panel 102 and an outer panel orskin 103. The space existing between the panels 102 and 103 is filledwith a suitable insulating material 104 which may be of the preformedpackage type and thespace existing between the panels 101 and 102communicates with the various air ducts 105 provided within a series ofmain floor channel members 106. At the sides of the coach,longitudinally extending resilient sealing members 110 are supported onthe side sills 111 between wooden beams 112 and sill flanges 113. Thesub-floor consists of a block of insulating material 114 supported on aplate 115 riveted to the side sills 111. The serpentine conduit 116which contains the heating fluid, instead of being disposed within atrough on the upper side of the channel members 106 is actuallycontained within the air ducts 105 and the coil bends 117 are supportedon the resilient sealing members 110, as are also the return lines 118associated with the tubing. The plate 115 is supported on a series ofI-beams 119 which, in turn, are carried on transverse structural members120.

In the construction just described, the wooden beams 112 prevent anydirect metal-to-metal contact between the side sills 111 and the metalfloor proper. These beams thus serve the dual function 'of structuraland insulating members so that no appreciable amount of heat will belost by conduction through the composite floor structure. above, theheating system operates in substantially the same manner as described inconnection with the form of the invention illustrated in Figs. 1 to 5inclusive.

We claim:

1. In a vehicle construction, a composite floor including a sub-floorand a main floor assembly, said main floor assembly comprising aplurality of generally U-shaped metal channel members each having asurface panel and spaced depending side flanges, said channel membersbeing arranged in contiguity with adjacent side flanges abutting eachother and supported on the sub-floor, thus providing in combination withthe latter a series of parallel air ducts beneath the respective surfacepanels, tubing adapted to contain a heating fluid disposed below thelevel of said surface panels and having straightaway portions ex- Exceptfor the structural dilferences noted tending longitudinally andco-extensively with the respective channel members and arranged toradiate heat through said surface panel into the interior of saidvehicle and also radiate heat interiorly of the air ducts, andconnections for the ends of said straightaway portions exteriorly of thechannel members.

2. In a vehicle construction, a composite floor including a sub-floorand a main floor assembly, said main floor assembly comprising aplurality of generally U-shaped inverted channel members each having asurface panel and spaced depending side flanges, said channel membersbeing arranged in contiguity with adjacent side flanges abutting eachother and supported on the sub-floor, thus providing in combination withthe latter a series of parallel air ducts beneath the respective surfacepanels, the surface panel of each channel member being formed with adepending longitudinally extending coextensive trough portion havingopen ends and also opening upwardly and the bottom of which projectsinto the air duct, tubing adapted to contain a heating fluid, saidtubing having straightaway portions disposed within and substantiallyfilling said trough portions, and portions extending beyond the ends ofthe channel members for connecting the ends of said straightawayportions exteriorly of the ends of the channel members, and a removablecover plate closing the upper side of each trough member, said surfacepanels and cover plates presenting a continuous upper floor surface.

3. In a vehicle construction, the combination set forth in claim 2characterized in that said tubing is continuous and is comprised ofrelatively thin, deformable sheet metal and each of said cover plates isformed with an expansive tubing-engaging underneath surface designed toengage and compress the tubing within the trough portion of the channelmember with which the cover plate is 6 associated to force the metal ofthe tubing into intimate heat-transfer contact with said trough portion.

4. In a vehicle construction, in combination, a composite floor andhollow side walls partially defining therebetween a passenger enclosure,said floor including a subfloor and a main floor assembly, said mainfloor assembly comprising a plurality of generally U-shaped invertedchannel members each having a surface panel and spaced depending sideflanges, said channel members extending transversely of the vehicle andbeing arranged in contiguity with adjacent side flanges abutting eachother and supported on the sub-floor, thus providing in combination withthe sub-floor a series of parallel air ducts beneath the respectivesurface panels, said air ducts communicating at opposite ends with theinterior of said hollow side walls, the surface panel of each channelmemher being formed with a longitudinally extending coeX-- tensivetrough portion presenting a convex inner face within the air duct of themember, a continuous tubing having straightaway portions disposed withinand substantially filling said trough portions and having reverse bendsconnecting the adjacent ends of said straightaway portions exteriorly ofthe ends of the channel members, a removable cover plate closing theupper side of each trough member, said surface panels and cover platespresenting a continuous upper floor surface, grilles establishingcommunication between the interior of said side walls and the passengercompartment, a header common to all of said air ducts for supplying airunder pressure to the latter, means for circulating a heating fluidthrough said continuous tubing, and means for supplying air underpressure to said header.

5. In a vehicle construction, the combination set forth in claim 4characterized in that said header comprises an elongated tubularstructure embedded within the subfloor and opening upwardly into eachair duct.

6. In a vehicle construction, the combination set forth in claim 5characterized in that the header opens into each air duct centrally ofthe latter so that air delivered to the duct may divide and flowoutwardly in opposite directions toward the side walls.

7. In a vehicle construction, the combination set forth in claim 4characterized in that the trough portions of each channel member iscentrally spaced between the channel side flanges and wherein the headercomprises an elongated tubular structure embedded within the subfloorand opening upwardly into each air duct centrally thereof andimmediately below the trough portion thereof whereby air delivered tothe ducts may divide and flow in opposite directions longitudinally ofthe ducts toward the vehicle side walls.

8. In a vehicle construction, in combination, a composite floor andhollow side walls partially defining therebetween a passenger enclosure,said floor including a subfloor in the form of a block of heatinsulating material and a main floor assembly disposed above thesub-floor, said main floor assembly comprising a plurality of generallyU-shaped inverted channel members each having a surface panel anddepending side flanges, the lower ends of the side flanges resting uponsaid sub-floor, said channel members being arranged in contiguity andextending transversely of the vehicle thus providing in combination withthe sub-floor a series of adjacent transverse air ducts beneath therespective surface panels, said ducts communicating with the interior ofthe side walls at opposite sides of the vehicle, a continuous tubinghaving straightaway portions disposed below the level of said surfacepanels and extending centrally and longitudinally of the respectivechannel members, said tubing having reverse bends connecting theadjacent ends or said straightaway portions beyond the ends of thechannel members, grilles establishing communication between the interiorof said side walls and the passenger compartment, a header embedded inthe upper face of said block of heat insulating material andcommunicating upwardly with each of said air ducts, means forcirculating a heating fluid through said tubing, and means for supplyingair under pressure to said header.

9. In a vehicle construction, a hollow floor and hollow side walls incommunication with said hollow floor, said floor and walls definingtherebetween a passenger compartment, said floor presenting an upperplane floor surface interrupted at spaced regions by the provisiontherein of a series of parallel transversely extending troughspresenting convex heat radiating surfaces interiorly of the hollowfloor, a continuous tubing bent in serpentine fashion to provideparallel straightaway portions connected by reverse bends at the endsthereof positioned on said floor surface with the straightaway-portionsthereof substantially filling said troughs, means covering the uppersides of said troughs to conceal the tubing therein and present a smoothunbroken floor tread surface, means for circulating a heating mediathrough said tubing, and means for supplying air under pressure to theinterior of said hollow floor, there being openings in said hollow sidewalls establishing communication between the interior of the walls andthe passenger compartment.

10. In a vehicle construction, a composite floor including a sub-floorand a main floor assembly, said main fioor assembly comprising aplurality of generally U- shaped inverted channel members each having asurface panel and spaced depending side flanges, said channel membersbeing arranged in contiguity with adjacent side flanges having abuttinginterlocking engagement with each other and supported on the sub-floor,thus providing in combination with the latter a series of parallel airducts beneath the respective surface panels, the surface panel of eachchannel member being formed with a depend ing longitudinally extendingco-extensive trough portion having open ends and also opening upwardlyand the bottom of which projects into the air duct, tubing adapted tocontain a heating fluid, said tubing having straightaway portionsdisposed within and substantially filling said trough portion, andportions extending beyond the ends of the channel members for connectingthe ends of said straightaway portions exteriorly of the ends of thechannel members, and a removable cover plate closing the upper side ofeach trough member.

11. In a vehicle construction, the combination set forth in claim 10characterized in that one longitudinal edge of said cover plate has aninterlocking engagement with said channel member, and means are providedalong the other longitudinal edge of the cover plate for releasablvsecuring it to said channel member.

References Cited in the file of this patent UNITED STATES TATENTS1,681,582 Fjelstad Aug. 21, 1928 1,995,481 Myers Mar. 26, 1935 2,191,526Flogans Feb. 27, 1940 2,265,536 McFarlane -2 Dec. 9, 1941

